Belfast Telegraph

Sunday 20 April 2014

Questions and answers: Japan nuclear fallout

Members of a Korean rescue team walk through an area damaged by earthquake and tsunami after a 9.0 magnitude strong earthquake struck on March 11 off the coast of north-eastern Japan, on March 15, 2011 in Sendai, Japan. The quake struck offshore at 2:46pm local time, triggering a tsunami wave of up to 10 metres which engulfed large parts of north-eastern Japan. The death toll continues to rise with fears that the official death count could well reach up to 10,000 in "the most tragic event in Japanese history since World War Two".

Q How real is the threat of atomic meltdown in Japan?

A With conflicting reports on the stability of reactors at the Fukushima Daiichi plant, it is hard to tell how dangerous the situation really is. More than 200,000 people have been evacuated and another 140,000 ordered to stay indoors.

But the Japanese government continues to play down radiation fears, saying rising levels are due to rubble rather than continuing leaks.

Professor Matthew Zepf of Queen’s University said it is “impossible” to assess the real risks. “It sounds like the government doesn’t know for sure as the experts are keeping their distance from the reactors,” he said.

Q What is the worst case scenario?

A If another reactor explodes, there could be a serious release of radiation. Radiation, consisting of small particles of radioactive energy, can lead to the contamination of the human body, plant life and the animal food chain.

According to Professor Zepf, levels are unlikely to be as high as leaks after the Chernobyl disaster. “The worst case is that one of the reactors loses its containment completely and a large amount of radiation escapes,” he said. “At Chernobyl, the reactor core was allowed to catch fire, meaning it released a huge amount of energy. That is less likely in Fukushima but it could still happen.”

Q Where is the radiation likely to spread to?

A The prevailing winds suggest that any radiation would be blown out to sea rather than inland to nearby towns and cities. A worst case scenario could result in radiation leaks in a 20-mile radius of the power plant, but it is unlikely the effects would be felt further afield.

Q Should people in Northern Ireland be afraid?

A ”Absolutely not,” said Professor Zepf. “There is no chance whatsoever that radiation over there will make it over here in any concentrated form.” While concerns have been raised over the impact of nuclear fallout across the rest of the world, experts have said the threat to Northern Ireland is minimal.

The effects of radiation decrease over distance, and with nearly 6,000 miles between here and Japan, local people have no need to worry.

Q What are the health risks of radiation exposure?

A Exposure to radiation over long periods of time or in high quantities can lead to radiation poisoning or, in extreme cases, cancer.

Symptoms include nausea, fever and decreased white blood cell count.

Potassium iodide tablets are often given out to people at risk of contamination, and children are more likely to suffer than adults.

Q What can people do to protect themselves?

A Locals near Fukushima have been urged to stay indoors and keep all rooms airtight, with doors and windows closed.

Radiation can spread through most materials, with the exception of lead or concrete, and there is very little that can be done to prevent it spreading in fallout zones.

Anyone who comes into contact with radiation must remove all clothing immediately and wash with soap and water.

Q How long will it take |for the situation to return to normal?

A If a serious explosion takes place, an exclusion zone around the affected nuclear site could be screened off for years or even decades. The dangers of radiation decrease over time, but if the leak is severe access to the area would remain dangerous.

The nuclear plant would have to be abandoned and work resumed elsewhere. “If the worst case scenario happens, the 20-mile zone could be a real mess for years to come,” said Professor Zepf.

Q Is atomic power still safe to use?

A Events in Japan have reignited the debate, with experts arguing for safety reassessments at plants including Sellafield in England. All nuclear plants have internal safety mechanisms, meaning they are more stable than most industrial reactors.

Even if a reactor cooler fails, the nuclear material is in a sealed containment vessel, so no radiation should leak out. The risk of instability is increased by large-scale interferences such as earthquakes.

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